PROJECT SUMMARY/ABSTRACT The specific aims of this three-year R34 are to prepare for a clinical trial by (1) developing the protocol and resources for a consultation-liaison service-based collaborative care team (CCT) intervention to address untreated opioid and alcohol use disorders (OAUDs) among hospitalized inpatients and actively link them to follow-up care, and by (2) conducting a pilot RCT to assess (a) implementation feasibility; and (b) acceptability among patients and providers. The study is of critical importance to public health because millions of people in the United States need, but do not receive, treatment for substance-use disorders. OAUDs are of particular concern because of high rates of morbidity, mortality, hospitalizations, and readmissions, as well as the increasing incidence of opioid-use disorders and associated medical consequences and overdose deaths. Moreover, OAUDs are the most common substance use disorders among medical inpatients. However, despite high prevalence, few inpatients with OAUDs receive evidence-based treatments while in the hospital. Most physicians and other providers in acute hospital settings are not trained to assess or manage patients with OAUDs, contributing to low rates of OAUD identification and treatment initiation. Pharmacotherapies to address OAUDs are effective for use across medical settings but are seldom initiated in hospitals or recommended as part of follow-up care. Inpatient hospitalization offers a pivotal opportunity to decrease unmet need. Starting treatment in the hospital and effectively linking patients with follow-up care could not only improve outcomes, but also could decrease high rates of hospital readmission and ultimately lower costs. The current standard of care for hospitalized patients with OAUD?screening, brief intervention and referral to treatment?is not effective for those with OAUDs, possibly because it does not include initiation of medication or facilitate linkage to follow-up OAUD care. Barriers to OAUD treatment for inpatients include lack of expertise on the medical team, absence of an organized system for assessing and treating patients with OAUD, patient ambivalence about treatment, and lack of follow-up after discharge. The CCT will consist of a psychiatrist and care manager team with OAUD expertise who provide population-focused monitoring and measurement-based decision-making to support the medical team. The CCT will use evidence-based components, including a motivational interviewing-based therapeutic intervention, targeted discharge planning, and active referral. To develop the protocol, we will draw from our prior work in primary care and other evidence-based resources, and obtain input from a stakeholder advisory board comprised of patients and providers. To assess feasibility, we will enroll 80 patients admitted to the hospital over 5 months in a pilot RCT and collect baseline and 1-month follow-up data. To determine acceptability, we will conduct interviews with providers and patients. The proposed study would be the first to test a consultation-liaison service-based CCT to improve care for inpatients with OAUD.